A Berkeley engineer pleaded no contest to poisoning a coworker with cadmium after hidden-camera video caught him spiking her water, and now wants the felony erased.
David Xu spent nearly 18 months putting cadmium into Rong Yuan’s food and water at Berkeley Engineering and Research. In early 2019, a camera she hid at her desk recorded him tampering with her bottle.
Yuan suffered debilitating symptoms, repeated hospital visits, and the fear she was dying of a terminal illness. Her parents also drank the poisoned water without knowing it. Xu was arrested in March 2019 on attempted murder and poisoning charges, then released on $2 million bail.
Years later, under a plea bargain offered by then-Alameda County District Attorney Pamela Price, the attempted murder counts were dropped. Xu pleaded no contest to a single felony poisoning charge. He received two years of probation, one day of credited jail time, and an order to pay $7,058 in restitution, far below the nearly $500,000 Yuan sought.
He finished probation in March and is now asking a California court to dismiss the felony under the state’s expungement statute. Judges are bound to grant those dismissals when every probation term has been met.
Yuan emailed colleagues on Nov. 27, 2018, to report severe vomiting and take a sick day. Xu answered with concern that pointed elsewhere.
He told her to stay home and blamed the office.
Before the hidden-camera footage, Xu wrote that she should work from home until she felt better and added a simple explanation for her illness.
"You should work from home until you feel better. No reason to rush in,"... "I think BEAR is moldy."
Yuan set up the camera at her desk in early 2019. The video showed Xu handling her water bottle. That recording ended the mold story and led to his arrest that March.
NY Post reporting laid out the stretch of poisoning between 2017 and 2019, the arrest, and the later plea. The San Francisco Standard carried Yuan’s account of what the months of cadmium exposure did to her.
Yuan did not describe mild discomfort. She described a body shutting down and a belief that she might not survive.
"My blood was frozen,"... "I almost died. I experienced death so, so close so many times. I cannot let him go."
Those words sit beside the charging history. Prosecutors initially filed attempted murder along with poisoning. The metals work at BEAR gave Xu access and technical cover that ordinary workplace disputes never provide. Cadmium is not a prank substance. It is a toxic heavy metal.
After the arrest, Xu’s conditions eased over time. He won repeated modifications to home confinement. Travel restrictions were eventually lifted entirely. The case moved from a $2 million bail hold to a negotiated outcome that erased the most serious counts.
In late 2023, the plea bargain came from the office of then-District Attorney Pamela Price. Attempted murder charges disappeared. Xu admitted no contest to one felony poisoning count.
The sentence that followed was two years of probation and a single day of jail credit. Restitution was set at $7,058. Yuan had asked for nearly half a million dollars to cover what the poisoning cost her.
Price left office after that period. The deal itself remains the record. A man caught on camera contaminating a coworker’s water, after nearly a year and a half of the same conduct, walked away without a trial on the attempted murder allegations and without serious custody time.
Xu completed probation in March. He is now asking the court to formally dismiss the felony conviction.
California’s expungement rules leave judges little room once probation is finished cleanly. Defendants who meet every term are entitled to the dismissal. The felony poisoning mark Xu accepted in the plea can be cleared under that statute.
Yuan’s statement that she “cannot let him go” collides with a system that has already reduced the case from attempted murder to a single count, limited custody to one credited day, capped restitution in the low thousands, and now faces a mandatory path to wiping the conviction.
No motive appears in the public account. What does appear is the method, the duration, the video, the medical collapse Yuan described, the parents’ accidental exposure, the original charges, the plea under Price, and the numbers that followed.
A coworker who says she brushed against death still lives with the result. The man the camera caught is moving to clear his name under state law that treats finished probation as the end of the story.
When prosecutors trade attempted murder for a single poisoning count and a day of jail, victims learn exactly how much their suffering weighs on the ledger.
